Have Node::document() return a reference instead of a pointer

Source/core/page/Frame.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Simon Hausmann <hausmann@kde.org>
  *                     2000 Stefan Schimanski <1Stein@gmx.de>
  *                     2001 George Staikos <staikos@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2005 Alexey Proskuryakov <ap@nypop.com>
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
@@ skipping 60 matching lines @@
 namespace WebCore {
 
 using namespace HTMLNames;
 
 DEFINE_DEBUG_ONLY_GLOBAL(WTF::RefCountedLeakCounter, frameCounter, ("Frame"));
 
 static inline Frame* parentFromOwnerElement(HTMLFrameOwnerElement* ownerElement)
 {
     if (!ownerElement)
         return 0;
-    return ownerElement->document()->frame();
+    return ownerElement->document().frame();
 }
 
 static inline float parentPageZoomFactor(Frame* frame)
 {
     Frame* parent = frame->tree()->parent();
     if (!parent)
         return 1;
     return parent->pageZoomFactor();
 }
 
@@ skipping 204 matching lines @@
     // https://bugs.webkit.org/show_bug.cgi?id=18585
     if (!object->isRenderPart())
         return 0;
     return toRenderPart(object);
 }
 
 Frame* Frame::frameForWidget(const Widget* widget)
 {
     ASSERT_ARG(widget, widget);
 
-    if (RenderWidget* renderer = RenderWidget::find(widget))
+    if (RenderWidget* renderer = RenderWidget::find(widget)) {
         if (Node* node = renderer->node())
-            return node->document()->frame();
+            return node->document().frame();
+    }
 
     // Assume all widgets are either a FrameView or owned by a RenderWidget.
     // FIXME: That assumption is not right for scroll bars!
     ASSERT_WITH_SECURITY_IMPLICATION(widget->isFrameView());
     return toFrameView(widget)->frame();
 }
 
 void Frame::clearTimers(FrameView *view, Document *document)
 {
     if (view) {
@@ skipping 107 matching lines @@
 Document* Frame::documentAtPoint(const IntPoint& point)
 {
     if (!view())
         return 0;
 
     IntPoint pt = view()->windowToContents(point);
     HitTestResult result = HitTestResult(pt);
 
     if (contentRenderer())
         result = eventHandler()->hitTestResultAtPoint(pt, HitTestRequest::ReadOnly | HitTestRequest::Active | HitTestRequest::DisallowShadowContent);
-    return result.innerNode() ? result.innerNode()->document() : 0;
+    return result.innerNode() ? &result.innerNode()->document() : 0;
 }
 
 PassRefPtr<Range> Frame::rangeForPoint(const IntPoint& framePoint)
 {
     VisiblePosition position = visiblePositionForPoint(framePoint);
     if (position.isNull())
         return 0;
 
     VisiblePosition previous = position.previous();
     if (previous.isNotNull()) {
@@ skipping 262 matching lines @@
     if (!m_page)
         return 0;
 
     double ratio = m_page->deviceScaleFactor();
     if (RuntimeEnabledFeatures::devicePixelRatioIncludesZoomEnabled())
         ratio *= pageZoomFactor();
     return ratio;
 }
 
 } // namespace WebCore